ABSTRACT
This chapter outlines causes of diarrhea. Diarrhea and dysentery are among the major symptoms of acute enteric infection. The normal bacterial flora may be involved both in the prevention and the amplification of the effects of infection. Bacteriological studies of diarrhea have traditionally concentrated on the identification of bacterial pathogens. This approach has resulted in identification of many bacterial species associated with diarrheal illness. When discussing bacteria as a cause of diarrhea it is important to distinguish two groups of organisms in terms of their ecological association with the gut. The initiation of infection by most intestinal pathogens is dependent on their ability to reach the intestine and to attack the intestinal mucosa. Fermentation of unabsorbed metabolites can potentiate the osmotic effects of intestinal infection. Interactions between the bacteria must play an important role in determining both the total numbers and relative frequency of the various species.
